1. Field of the Invention
The invention generally relates to the growth of epitaxial silicon (Si) or silicon germanium (SixGe1-x, for simplicity, we use SiGe in the following description) on various semiconductor crystal surfaces and more particularly to an improved method that reduces the amount of oxygen on the semiconductor crystal surfaces, without roughening the surfaces.
2. Description of the Related Art
The surfaces of Si wafers normally become covered with a thin native oxide layer when exposed for more than a few minutes in an oxygen-containing environment. In epitaxial processes, the residual oxide (or oxygen contamination) on the surface of the substrate must be minimized to enable the growth of high-quality epitaxial films. Additionally, if the active region of an electrical device fabricated on the substrate is close to the epitaxial growth interface, residual oxygen at the interface may affect the operation or performance of the device. The invention described below reduces the amount of residual oxygen without substantially roughening the surface.